Energetic, structural and mechanical properties of terraced interfaces

Taking the well-understood Cu-Ni {111} semi-coherent interface as a prototype, we demonstrate an important, yet long-been-overlooked, size effect on the properties of terraced interfaces — i.e. the facet length scale effect. Interfacial facets are considered as super interface disconnections (SIDs). We then studied the SID's size effect on the energy, structure, and mechanical response of terraced interfaces by using atomistic simulations and defect theories. We found that the specific facet energy — therefore the specific energy of the terraced interface — exhibits a periodic change with the SID's size. The periodic change is associated with the quantized transitions in their dislocation structures. Correspondingly, the mechanical response of terraced interfaces also exhibits clear regime shifts, as reflected in changes in the nucleation and emission mechanisms for lattice dislocations.